Transmission characteristics of wearable transmitter and stationary receiver through human body

Human body communication (HBC) is expected to become an increasingly important man-machine interface because a transmission path is established only when a user touches a target device. In this research, we investigated HBC between a stationary device touched by the palm or finger and a wearable device worn on the wrist. The transmission characteristics between the devices and the electric field around the arm model were determined via electromagnetic field analysis. The transmission characteristics from the wearable device to stationary device decreased by 2 dB per 5 cm as the transmitter was moved away from the receiver. Next, the body trunk and measurement equipment were introduced to the simulation to analyze their effects on the transmission characteristics. It was found that the transmission characteristics were improved by 6 dB when the body and measurement equipment were added. This suggests that the effects of the body and measurement equipment on the transmission characteristics cannot be ignored when making comparisons between simulations and experiments.